Medical science, and especially the practice of angioplastic surgery, has experienced dramatic advances during the past several decades. More recently, the use of thermally-heated metallic tips for catheters has been suggested for ablating human atherosclerotic plaques and recanalizing obstructed low risk peripheral arteries. Those thermal tip catheters which have been so used require electrical or laser energy to heat the catheter tip to a desired temperature for carrying out the desired thermal surgery.
For example, experimental laser thermal angioplasty has been successfully performed in human peripheral arteries with low risks of vessel perforation (Sanborn et al, JACC 1985; 4:934-8), and preliminary studies regarding laser thermal angioplasty are ongoing in patients with coronary artery disease (Lancet 1986 II: 214-5; and Cumberland et al, Lancet 1986 I: 1457-9). In addition, electrical thermal tip catheters have also been designed and feasibility studies are being carried out (Lu et al, abstr. circ. 1986); these require about 10-15 watts for effective tissue ablation.
However, while electrical and laser thermal angioplasty has greatly improved, has achieved limited success and has some potential, the danger of exposing unnecessary electrical shock and other injuries to patients, particularly due to an electrical source or laser operating in a patient's blood vessels, is still a major undesired probability. Electrical and laser thermal angioplastic apparatus also have minimal control over the rate of tissue ablation due to lack of temperature monitoring of the working (distal) end or tip of the catheter.
Furthermore, when employing laser thermal angioplasty, a large technical and support staff are usually required to operate the laser apparatus effectively and safely. Moreover, laser system are necessarily cumbersome and nonportable, therefore restricting their practicality. Both the electrical and the laser thermal tip catheter systems are expensive to manufacture and require regular upkeep and maintenance to assure system operation and patient safety.
No thermal tip catheter or the like system has previously been available for successful angioplasty which does not require electrical or laser energy to heat the catheter tip. The need exists for a thermal tip angioplastic device which is safe, effective, less expensive, and easy to operate with minimal technical and support staff.